The Gastroenterology Teaching Project

Alimentary Tract Motility: Stomach, Small Intestine, Colon and Biliary Tract

UTP 10B

Table of Contents

MOTILITY

  1. Introduction
  2. Methods of Studying Alimentary Motility
  3. Functional Organization
  4. Functional Segments
  5. Motility Patterns
  6. Gastrointestinal Smooth Muscle
    1. Anatomic Arrangement
    2. Initiation of Contraction
    3. Signal Transduction
      1. Chemico-Mechanical Coupling - Contraction
      2. Chemico-Mechanical Coupling - Relaxation
      3. Electro-Mechanical Coupling - Contraction
      4. Electro-Mechanical Coupling - Relaxation
  7. Neural and Intercellular Communication
    1. Nerve-Muscle Communication
    2. Gap Junctions
  8. Control of Motility
    1. Myogenic Control
    2. Neural Control
    3. Levels of Control
    4. Propagated and Localized Contractions
    5. Propagated Contraction (Peristalsis)
    6. Inhibitory Reflexes
  9. Gastrointestinal Motor Patterns - Fasting and Fed
    1. Stomach and Small Intestine Display Two Different Patterns
      1. Fasting Motor Pattern
      2. MMC Propagation
    2. Control of MMC
      1. Hormonal Control
      2. Neural Control
    3. Fed Motor Pattern

GASTRIC MOTILITY - NORMAL FUNCTION

  1. Overview
  2. Reservoir Function - Proximal Stomach
    1. Receptive Relaxation
    2. Compliance
    3. Regulation of Proximal Gastric Motility
    4. Neuro-humoral Control of Gastric Emptying
  3. Preparatory Chamber and Emptying Regulation - Distal Stomach, Pyloric Antrum, and Sphincter
    1. Gastric Slow Waves & Peristalsis
      1. Gastric Slow Waves
      2. Gastric Peristalic Waves
    2. Gastric Emptying
      1. Homogenization & Emptying of Digestible Solids
      2. Emptying of Undigestible Solids
    3. Control of Gastric Emptying
      1. Volume
      2. Osmolality
      3. PH
      4. Caloric Content
      5. Caloric-feedback Inhibition of Gastric Emptying

GASTRIC MOTOR DYSFUNCTION

  1. Overview
  2. Delayed Gastric Emptying
    1. Failure of the Driving Force
      1. Failure of Normal Propagation of Gastric Slow Waves
      2. Decreased Electro-mechanical Coupling
      3. Neuromuscular Causes of Decreased Frequencey and Amplitude of Gastric Peristalsis
    2. Increased Pyloric Resistance
  3. Pyloric Sphincter Incompetence
    1. Duodenogastric Reflux
    2. Dumping Syndrome
  4. Increased Gastric Emptying
    1. Motor Effects of Vagotomy
      1. Vagotomy Results in Rapid Gastric Emptying of Fluids
    2. Impaired Negative Feedback from Duodendum

SMALL INTESTINAL MOTILITY - NORMAL FUNCTION

  1. Overview
  2. Intestinal Slow Waves
  3. Intestinal Peristalsis
  4. Intestinal Motor Patterns
    1. Fasting
    2. Fed
      1. CNS (vagal) Input Necessary for Fed Pattern
      2. Effect of Motor Pattern on Absorption
      3. Effect of Calories on Duration of Fed Pattern
      4. Effect of Type of Food on Duration of Fed Pattern
      5. Myoelectric Characterization of Fed Pattern
      6. Propagated and Segmental Myoelectric Activity
      7. Ratio of Segmented to Propagated Activity Varies with Motor Pattern
      8. Summary of Myoelectric Activities

SMALL INTESTINAL MOTOR DYSFUNCTION

  1. Overview
  2. Changes in Slow Wave Frequencey and Velocity
    1. Increased Slow Wave Frequencey
    2. Decreased Slow Wave Frequencey
    3. Decreased Slow Wave Velocity
    4. Absent Slow Waves
  3. Alterations in Spike Potential Activity (Enteric Nervous System Abnormalities)
    1. Scleroderma
    2. Acute Mechanical Intestinal Obstruction
    3. Vomting
    4. Partial Obstruction Alters Fed Pattern
    5. Enteric Pathogens, Enterotoxins and Cathartics Produce Abnormal Myoelectric Patterns in Association with Diarrhea
  4. Abnormalities in the Generation of MMCs
    1. Failure to Generate MMCs
    2. Abnormal Control of MMCs
  5. Smooth Muscle Failure

COLON MOTILITY

  1. Overview
    1. Anatomy
    2. Functional Difference Between Right and Left Colon
  2. Contraction Patterns
  3. Control of Motility
    1. Myogenic Control
      1. Slow Wave Frequencey
      2. Slow Wave Propagation
      3. Electro-mechanical Coupling
    2. Neural Control
      1. Enteric Nervous System Control
      2. Extrinsic Nervous Control
        1. Parasympathetic Control-vagus Nerves
        2. Parasympathetic Control-pelvic Nerves
        3. Sympathetic Control
    3. Movement of Colonic Contents
      1. Mixing of Colonic Contents
      2. Ileocecal Sphincter
      3. Response to Feeding
    4. Defecation

COLON MOTOR DYSFUNCTION

  1. Overview
  2. Loss of Innervation
    1. Extrinsic Innervation
    2. Intrinsic Innervation
      1. Hirschsprung's Disease
      2. Laxative Abuse
  3. Slow Wave Abnormalities
    1. Diarrhea induced by Infectious Agents and Sodium Ricinoleate (caster oil)
    2. Irritable Bowel Syndrome
    3. Diverticulosis
  4. Abnormalities in Spike Potential Generation
    1. Comparison of Normal and Functional Bowel Disorders
    2. Alteration in Postprandial Spike Response
  5. Smooth Muscle Abnormalities
  6. Common Gastrointestinal Disorders of Uncertain and Probably Multiple Etiologies
    1. Irritable Bowel Syndrome
    2. Diverticular Disease
    3. Incontinence

BILIARY TRACT MOTILITY - NORMAL FUNCTION

  1. Overview
    1. Anatomy
    2. Bile Flow
      1. Determinants of Flow
      2. Pressures and Flow
  2. Gallbladder
    1. CCK is the Primary Stimulus for Gallbladder Contraction
    2. Both CCK and Acetylcholine Stimulate Gallbladder Contraction
    3. Bile Flow into Duodenum is Determined by Gallbladder Contraction and Sphincter of Oddi Relaxation
  3. Sphincter of Oddi
    1. Functions of the Sphincter of Oddi
    2. Basal Tone and Phasic Contractions
    3. Propagation of Phasic Contractions
    4. CCK Decreases Sphincter of Oddi Pressure
    5. Drugs Alter Sphincter of Oddi Pressure
  4. Bile Flow
    1. Fed - Simulated by CCK Infusion
    2. Fasting

BILIARY TRACT MOTILITY - NORMAL FUNCTION

  1. Cholelithiasis - Gallbladder Dysmotility
  2. Sphincter of Oddi Dysfunction
  3. Morphine Produces Sphincter of Oddi Dysfunction

 
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